No Forward with Atomic 4

[msc1212]

Sigh. My Atomic 4 (1984) is giving me a very curious problem. The engine stalls in forward. When it's cold it will run in forward for about a minute and then gradually depower and stall. When it's hot it stalls immediately. The motor runs fine in Neutral and in reverse. The problem gradually intensified over the past few weeks. I realize this is likely a problem with the pressure plate in the clutch (which will require a rebuild) but before I pull the engine I have to ask "am I missing something obvious". The forward drive on the atomic is almost bullet proof. My mechanic has never seen one fail.

I've checked the prop and there is nothing wrapped that could be causing this.

Any thoughts?
thanks

Michael
Impromptu E35Mk11

 

[Emerald]

It actually could be a failing fuel pump (or restriction in the supply side such as a clogged filter). When I have an engine that will idle but not pull a load without dying, the fuel flow side is one of the first things I check. I've had several experiences with a failing fuel pump providing enough flow to idle, but not run under load. For it to be related to going into gear, you're looking at what is binding downstream to put so much load as to stall the engine, e.g. something wrong in the transmission or wrapped around your prop. Put the engine in gear, not running, and see if you can turn it over by hand. Do you have the crank that fits into the front cover? If so, this is easy to check. If it turns over fine by hand in gear, I'd hit the fuel side next.

 

[msc1212]

Thanks for responding. I should have been more complete in my description. The first thing I did when this started was change the fuel filter and the fuel pump. The problem persisted. The thing is, I can run the engine in reverse without a problem. I backed out of my club yesterday to go sailing and then backed in at the end. It made for some strange looks from the marina folk but who cares, I wanted to go sailing.

 

[tenders]

Seek thee assistance at the moyermarine.com forums. No slight intended to present company here but nowhere else will you find more Atomic Four expertise.

The A4 uses much less fuel going in reverse, which has implications for your symptoms. I agree that before you pull the engine there is a lot more troubleshooting that could be done and at least one adjustment to something called a "collar ring" that I've only read about myself.

 

[steven]

I second tenders advice to check at Moyer.

I have similar sounding problem - began about middles of this season. Just a guess but it may have to do with water in the gas caused by high ethanol content combined with high humidity. As I mentioned in another thread, in fwd. I can fuss with the choke a keep the engine running. In reverse, it's ok. An A4 is geared in reverse to get about 40% more rpm from the same throttle - I think that may have something to do with why reverse is ok - but the exact reason on why that might be so eludes me.

--Steve

 

[msc1212]

Thanks very much for the comments. I spent the last week researching on this sight and Moyer why I could have no problems in reverse and neural but not forward. The consensus was that this condition is rarely related to the "transmission" so I took all day Friday and looked at all the systems that would affect rpm - compression, timing, plugs, exhaust and fuel system. Guess what...the reason my motor was stalling in forward was because the fuel pump was grounded incorrectly. The fuel pump grounds to the block. The bolt that attaches the pump to the block was loose. When this was tightened the pump ran at it's proper capacity and I had forward. It was a miracle. I thought I was looking at a haul out and rebuild. Instead it was a single turn of a bolt. Who knew?

I was able to go for a sail today,, pulling out of the marina in forward rather than reverse.

Thanks.

Michael
Impromptu


Michael

 

[mherrcat]

Cool. Love the simple solutions! Similar situation with my car. One day it wouldn't start. Absolutely nothing; no "click", nothing. Had to have it towed to my mechanic. Turns out it was the positive wire from battery to starter was loose. Tighten it, started right up. Good, clean, tight connections seem to be one of the basics with electrical systems.